Thanks for the great advice!
I put the new tube in about as far as it would go without force. It was below the opening and beyond it. I measured the extra length and removed the tube and cut off the 'extra' - about 3/4 inch. This allowed me to get back into place and push it (see 'bend') so the end would now enter the opening.
Then it was just a matter of applying force to get it to seat flush. My wife used a 2 ft 3/4 extension applied to the bracket and a hammer from above while I worked it from below. It seated in no time - compared to the hours some of you suffered doing this project.
It's in. It's all scratched up and not pretty, but it works.
2003 F150 Supercrew Styleside, 4.6L